BackgroundHealth care workers (HCWs) are at risk for occupational stress. The negative effects of stress HCWs subsequently affect the quality of their job performance. Since 2014, there have been extensive changes in the primary health care system in Iran. Because evidence has shown that organizational change can cause stress in employees, this study was designed and conducted to explore the perceived job demands by HCWs in primary care centers after extensive organizational change.MethodA qualitative study was designed with a content analysis approach. Study data were collected through 11 semi-structured individual interviews and a focus group with HCWs.ResultsParticipants reported high stress at work. They reported various factors as stressful job demands. These factors included: organization's supervisory function (Weakness of the monitoring process, Unfair policies, Apply regulatory pressure), Role features (Role load, Role conflicts, Role ambiguity(,Workload )High workload, Not having time, Great variety of tasks), job insecurity (Lack of job security due to employment status, Concerns about payments, Lack of physical security, Uncertain job future), Working with clients (Different characteristics of clients, Harassment of clients to achieve their expectations, Tensions in client relationships, Lack of knowledge of clients about health care work instructions), Perceived job content (Annoying work with different units of the organization, Monotonous and repetitive tasks, Meaningless tasks, No attractive and no excitement).ConclusionCurrently, HCWs working in health centers are faced with various stressful situations. Most of the factors identified in this study overlap in increasing stress. The impact of workload and organizational oversight on occupational stress seems to be more pronounced. Given the important role of HCWs in promoting health, the design and implementation of effective interventions by policymakers to control stress in HCWs is essential.